I’m sorry, Dean.
Can we just talk about this scene for a second?
Cas is completely expecting to die here. He has accepted that he is going to die and does not believe for a second that he is going to survive this and yet he shows no fear of this fact. He shows no hesitation in what he has to do.
And now look at the look of sad resignation on his face in the last gif. The look of hopelessness. The look of pure and utter defeat and regret. But he’s not hopeless and resigned because he knows he going to die here. His defeat lies in having to leave Dean to cope with his betrayal. His fear lies with knowing Dean has been hurt by him and he’s about to die without being able to fix it.
His last words are, “I’m sorry, Dean.”
That is the biggest concern here on his face. Not that he is about to reach the end of an ancient life, not that he has no idea what’s going to happen to his own existence, and not that he is about to leave behind a long legacy, but that he is leaving behind the one life and legacy that made him feel alive, a man who doesn’t forgive him, a man he hurt. And it hurts Cas that he hurt Dean.
This is the face of a man who feels pain and resignation and regret and love and the pain of fucking it all up.
And the fear of not being able to make it right.